Charities are calling for new laws to protect the elderly as a study shows that more than 300,000 cases of abuse go undetected each year.

"Cases of abuse of the elderly uncovered by inspectors include care homes where residents were routinely tied to their beds and chairs, locked up or dragged around by their hair.

Other residents, many of whom had dementia, have been refused food and denied trips to the lavatory in punishment for "bad behaviour".

Investigations have revealed a woman of 85 who had her fingernails ripped off by a care worker, a 78-year-old covered in cigarette burns, and a number of thefts of pensions by care staff paid to look after the elderly.

Government research suggests that 340,000 pensioners suffer some form of physical, financial or emotional abuse each year.

Action on Elder Abuse investigated local authority records and found that fewer than a tenth of that number of cases are ever investigated by social services.

The charity, together with the Alzheimer's Society, Age Concern, Mencap, and the Commission for Social Care Inspection, is calling for laws to be introduced which would place a duty on all agencies which work with vulnerable adults to log and investigate reports of abuse – either in residential care or in family homes – and to share information with other agencies.

Currently, different bodies set their own rules about how to protect the frail elderly, and disabled, from harm.

The charities made the plea as part of submissions to a Government consultation on the protection of vulnerable adults, which closed yesterday.

Gary Fitzgerald, chief executive of Action on Elder Abuse, said: "We are simply not doing enough to protect old people facing abuse, and we are challenging the Government to listen and to introduce safeguards that make this a priority."

Neil Hunt of the Alzheimer's Society added: "We need to fight any abuse of people with dementia and that means putting systems in place early to avoid putting them at risk.""

You can reduce your risk of developing dementia by eating less salt/sodium.